Redundancy is a system design in which a component is duplicated so if it fails there will be a backup.

Continuity is the unbroken and consistent existence or operation of something over a period of time:

Although these concepts seem to be similar, their application in information technology that draws clear differences.  Redundancy relates to the design of a solution and its ability to remain operational in the event of a single loss, or single point of failure.  A good design will address the following:

• Duplication or replication of core functions
• Geographic separation
• Automated activation
• Multiple forms of connectivity consist of
  • Different suppliers
  • Different media
  • Different access methods

Continuity in technology adopts a more general view related to operational continuity versus solution continuity.  It is a given that operations can be stabilized with redundancy, however a 100% up time is not.  In those situations continuity takes over and addresses the following:

• What is the plan when operations of a system go offline
• How long can an outage be tolerated
• What is the cost of an outage
• What are the priority operational components in the system
• Are continuity rates clearly communicated with proper expectations